tree = [[[5, 1, 2], [8, -8, -9]], [[9, 4, 5], [-3, 4, 3]]]

root = 0

pruned = 0



def children(branch, depth, alpha, beta):

   global tree

   global root

   global pruned

   i = 0

   for child in branch:

    if type(child) is list:

      (nalpha, nbeta) = children(child, depth + 1, alpha, beta)

      if depth % 2 == 1:

      beta = nalpha if nalpha < beta else beta

   else:

     alpha = nbeta if nbeta > alpha else alpha

     branch[i] = alpha if depth % 2 == 0 else beta

     i += 1

   else:

     if depth % 2 == 0 and alpha < child:

       alpha = child

     if depth % 2 == 1 and beta > child:

       beta = child

     if alpha >= beta:

       pruned += 1

        break

    if depth == root:

      tree = alpha if root == 0 else beta

    return (alpha, beta)



def alphabeta(in_tree=tree, start=root, lower=-15, upper=15):

    global tree

    global pruned

    global root



    (alpha, beta) = children(tree, start, lower, upper)



    if __name__ == "__main__":

      print ("(alpha, beta): ", alpha, beta)

      print ("Result: ", tree)

      print ("Times pruned: ", pruned)



    return (alpha, beta, tree, pruned)



if __name__ == "__main__":

alphabeta()